Just in time

USGS, Caltech and others are developing a system that will issue warnings moments before an earthquake

Last month a magnitude 4.4 earthquake reminded everyone to get prepared for the inevitable Big One on the way. Scientists now say that in the next 30 years there is a 60 percent chance that an earthquake equal to or greater than the magnitude 6.8 Northridge earthquake will hit the Los Angeles area.

Wouldn’t it be great if there were some kind of system in place to warn people before the earth starts shaking? Doug Givens of the US Geological Survey in Pasadena is working on a program that will do just that.

“The basic concept is early warning, not earthquake prediction,” said Givens, coordinator of the Earthquake Early Warning System. “It is simply sensing and characterizing an earthquake that has already begun very rapidly. That gives you the ability to send warnings out in advance of the arrival of the strong shaking, which moves at about two miles per second through the Earth. We can communicate at the speed of light. So if you can detect the earthquake very fast, you can send a warning out to people in the surrounding area.”

Givens is working with scientists from Caltech, UC Berkeley and University of Washington in developing the system. There are currently test users trying out the demonstration system before it is released to the general public. Their biggest obstacle, however, is funding.

“The technology works,” Congressman Adam Schiff (D-Burbank) recently wrote on Facebook. “For example, test users in Pasadena had about four seconds warning before the shaking (from March 17’s earthquake) was felt in their area. Not much, but depending on how far away the epicenter is, the warning time may be greater and even a few seconds can mean the difference between finding cover and getting injured. Now it’s time to build the system — a relatively small investment that will save lives and pay for itself many times over the first time we have a major quake. I’m confident we’ll build the system — it’s just a matter of whether we’re going to do it before or after the next big quake. I’ll be fighting for a greater federal investment so we can be ready.”

So how much time will you get before the earthquake hits? It completely depends on how far away you are from the earthquake and how rapidly the system can send you the alert.

“Time is of the essence,” said Givens. “That’s why you need a lot of sensors (around Southern California) so you have some that are close to where any potential earthquake can occur. The amount of warning time can be anywhere from zero if you’re very, very close to the event to up to 90 seconds if it’s a very big earthquake and you happen to be very far away.”

Givens and his team are looking at every available possibility in terms of delivering the early warning, including cell phones, television, radio, computers, public address systems, highway signs, maybe even those old air raid sirens.

“The distribution will be over every means that we can find,” said Givens. “Everything that we can do in a practical sense we’ll try to do.”